Electrically conductive materials are used for a variety of purposes in the fabrication and assembly of electronic devices, integrated circuits, semiconductor devices, passive components, solar cells, solar modules, and/or light emitting diodes.
For example electrically conductive materials, such as electrically conductive adhesives (ECAs) can be used to bond metallic electrodes to conductive surfaces to form an assembly. These assemblies, however, are vulnerable to environmental conditions, because high temperature and high humidity can cause the electrical contact resistance of the assemblies to increase substantially over time. The suspected mode of failure is electrochemical corrosion due to the formation of a galvanic cell in the presence of moisture, especially when the electrically conductive materials contain noble metals, such as silver, which have a higher electrochemical potential than the surrounding electrodes.
U.S. Publication No. 2002 0193467 A1 teaches one possible solution to improve the stability of the contact resistance over time. The disclosed electrically conductive materials comprise an effective amount of corrosion inhibitors to inhibit or reduce the surface corrosion. As corrosion inhibitors could affect the chemical or physical properties of an electrically conductive material it would be desirable to provide alternative formulations where a similar performance is achieved without using any corrosion inhibitor or where only a reduced amount of these materials is used.
Hence, there is a need for new curable compositions suitable for use as electrically conductive materials that are easy to handle and that exhibit a stable and low contact resistance even when these materials are used to form electrically conductive bonds between oxidizable substrates, which are exposed to harsh environmental conditions. Additionally it would be desirable to achieve the stable and low contact resistance without using any corrosion inhibitors or by using only a reduced amount of corrosion inhibitors.